LTC3547EDDB#TRMPBF Analog Devices

POWER LOSS (W) LTC3547 Dual Monolithic 300mA Synchronous Step-Down Regulator FEATURES DESCRIPTIO High Ef ciency Dual Step-Down Outputs: Up to 96% The LTC 3547 is a dual, 2.25MHz, constant-frequency, 300mA Output Current per Channel at V = 3V synchronous step-down DC/DC converter in a tiny 3mm IN Automatic Low Ripple Burst Mode Operation 2mm DFN package. 100% duty cycle provides low drop- (20mV ) out operation, extending battery life in portable systems. P-P Only 40A Quiescent Current During Operation Low output voltages are supported with the 0.6V feed- (Both Channels) back reference voltage. Each regulator can supply 300mA 2.25MHz Constant-Frequency Operation continuous output current. 2.5V to 5.5V Input Voltage Range The input voltage range is 2.5V to 5.5V, making it ideal for Low Dropout Operation: 100% Duty Cycle Li-Ion and USB powered applications. Supply current dur- Internally Compensated for All Ceramic Capacitors ing operation is only 40A and drops to < 1A in shutdown. Independent Internal Soft-Start for Each Channel Automatic Burst Mode operation increases ef ciency at Current Mode Operation for Excellent Line and Load light loads, further extending battery life. Transient Response An internally set 2.25MHz switching frequency allows 0.6V Reference Allows Low Output Voltages the use of tiny surface mount inductors and capacitors. Short-Circuit Protected Internal soft-start reduces inrush current during start- Ultralow Shutdown Current: I < 1A Q up. All outputs are internally compensated to work with Low Pro le (0.75mm) 8-Lead 3mm 2mm ceramic capacitors. The LTC3547 is available in a low DFN Package pro le (0.75mm) 3mm 2mm DFN package. The LTC3547 U APPLICATIO S is also available in a xed output voltage con guration, eliminating the need for the external feedback networks Cellular Telephones (see Table 2). Digital Still Cameras , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Wireless and DSL Modems Burst Mode is a registered trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, PDAs/Palmtop PCs including 6580258, 5481178, 6304066, 6127815, 6498466, 6611131. Portable Media Players Ef ciency vs Output Current TYPICAL APPLICATIO for V = 2.5V OUT 100 1 Dual Monolithic Buck Regulator in 8-Lead 3mm 2mm DFN 90 V IN 80 2.5V TO 5.5V 0.1 70 4.7F RUN2 V RUN1 IN 60 L2 L1 LTC3547 50 0.01 4.7H 4.7H V V OUT2 OUT1 2.5V AT 1.8V AT SW2 SW1 40 300mA 300mA 10pF 10pF 30 0.001 20 V = 2.7V IN V V FB2 FB1 V = 3.6V 10 IN GND 475k 475k 4.7F 4.7F V = 4.2V 237k 150k IN 0 0.0001 0.1 1 10 100 1000 3547 TA01 OUTPUT CURRENT (mA) 3547 TA01b 3547fa 1 EFFICIENCY (%) U ULTC3547 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) TOP VIEW V ............................................................... 0.3V to 6V IN V , V ......................................... 0.3V to V +0.3V FB1 FB2 IN V 1 8 V FB1 FB2 RUN1, RUN2 ..................................... 0.3V to V +0.3V RUN1 2 7 RUN2 IN 9 V 3 6 SW2 SW1, SW2 (DC) ................................ 0.3V to V +0.3V IN IN SW1 4 5 GND P-Channel Switch Source Current (DC) ...............500mA N-Channel Switch Sink Current (DC) ...................500mA DDB PACKAGE Peak SW Sink and Source Current (Note 5) .........700mA 8-LEAD (3mm 2mm) PLASTIC DFN T = 125C, = 76C/W Ambient Operating Temperature Range ... 40C to 85C JMAX JA EXPOSED PAD (PIN 9) IS GND MUST BE SOLDERED TO PCB Maximum Junction Temperature .......................... 125C ORDER PART NUMBER DDB PART MARKING Storage Temperature Range ................... 65C to 125C LTC3547EDDB LCDP LTC3547EDDB-1 LCPC Order Options Tape and Reel: Add TR Lead Free: Add PBF Lead Free Tape and Reel: Add TRPBF Lead Free Part Marking: